Typical electromechanical timers work with a rotating barrel moved by electrical motors and which have indentations whose position constitutes the different states of the equipment. The indentations open and close electrical contacts which directly switch on and off the equipment loads. In the present invention, electrical sensors move themselves in relation to a coded surface. In contrast with the electromechanical timers, these sensors are used merely to read the state of the equipment while the switching of the electrical loads is accomplished through the use of electronic circuitry thus conferring greater reliability, performance and durability.
In particular, the sensors may be electrical contacts which move over a printed circuit board, where the tracks constitute an encoding of the states. In this case, another advantage of the present invention over the electromechanical timers is the fact that the encoding of the states of the printed circuit board can easily be altered in contrast to the indentations of the rotating barrels which are normally injected in plastic.
In general, electronic timers need additional electronic displays to show the state of the operation which increases the price of the product. In the present invention, the display of the operation is simpler, consisting of an indicator disc which rotates together with the cogwheel. Moreover, when the sensors are electrical contacts moving over a printed circuit board, the alteration of the codes is simple compared to the need to change the mask in the manufacture of the micro-controller as is necessary in the case of electronic timers.